In the art of centrifuges, for example, of the general type disclosed in U.S. Pat. No. 3,970,470, a perforated basket or container is adapted to receive a load of material, such as sugar, which requires centrifuging to extract liquid and moisture from the material. Commonly, the container is mounted on top of a drive shaft which is rigidly connected to the bottom of the container, and the bottom of the drive shaft is supported by a thrust bearing which permits orbital movement of the container while the container is rotating. According to one system for rotating the container, a belt drive extends laterally from the bottom drive shaft for the container to the output shaft of a vertically arranged clutch-brake unit such as a unit disclosed in U.S. Pat. No. 3,924,715 which issued to the assignee of the present invention. The vertical input shaft of the clutch-brake unit is driven continuously by an electric motor which is located above and in vertical alignment with the laterally offset clutch-brake unit.
Another form of drive system for a centrifuge basket or container, incorporates an electric motor located directly below the container and having an armature or rotor mounted directly on the shaft supporting the bottom of the container. The armature or rotor of the electric motor orbits with the centrifuge container and is surrounded by an annular motor stator. If a sufficient annular gap is provided between the rotor and the stator, the stator may be secured directly to the frame of the centrifuge. As an alternative, the motor stator housing may be resiliently supported and connected through bearings to the drive shaft so that the entire motor including the stator and rotor gyrate with the basket or container.